1. Field of the Invention
This invention relates generally to the field of sterilizing and destroying the hypodermic needle component of a syringe so as to render it safe for disposal. This invention relates specifically to a portable apparatus which operates off of a rechargeable power source and which can operate while the power source is charging or when disconnected from the charging source. The invention incinerates and sterilizes the hypodermic needle component of the syringe by passing electricity continuously along portions of the needle component until significantly all of the needle portion has been burned due to the heat produced by the electrical resistance through the needle component, with the resistance heat also sterilizing any remaining portions of the needle component and the entry portal of the apparatus. The apparatus also comprises a fan which pulls air through a filter module causing any exhaust emission and pollutants to be filtered out by the filter module.
2. Prior Art
Current medical practice favors one-time use hypodermic needle syringes over reusable syringes. After a one-time use hypodermic needle syringe has been used, it must be disposed of properly. A used hypodermic needle syringe often poses a health hazard to any person coming into contact with a contaminated needle or syringe. The widespread exposure of contagious and fatal diseases multiplies this hazard.
The most common method for disposing of used hypodermic needle syringes is a "sharps"' container. A sharps' container merely is a plastic container into which the used hypodermic needle syringes are placed. When the container is full, a cap is placed on the container and the container is disposed of. Typically, a service picks up the full sharps' containers and disposes of the full containers either through incineration or in landfills. When destroyed in incinerators, the sharps' container provides a sufficient method of disposal of the used hypodermic needle syringes. However, sharps' containers suffer from several disadvantages. First, the used hypodermic needle syringes are not sterilized before being placed in the sharps' container. This can lead to unintentional contact with a contaminated needle. Second, if the sharps' containers are disposed of in a landfill, there always is the possibility that the sharps' container can inadvertently open or be broken, thus exposing the contaminated needles.
An electrical syringe needle destroyer is disclosed in U.S. Pat. No. 4,628,269 to Ch'ing-Lung. The Ch'ing-Lung device comprises a pair of spaced apart electrodes within a self-contained unit. The needle of the syringe is inserted into an opening in the unit until the base of the needle component is positioned between the two electrodes. When electricity is passed between the electrodes, the electricity causes the portion of the needle between the electrodes to melt, thus severing the needle from the syringe body. The needle portion falls into a collection means and can be disposed. The Ch'ing-Lung device may not destroy the needle, but merely severs the needle from the syringe body. Therefore, the Ch'ing-Lung device does not eliminate the dangers of contamination from the end of the needle, nor the safety hazard obvious from the possibility of having many loose needle heads in the unit. Furthermore, the Ch'ing-Lung device requires two-handed operation. Also, the electrodes do not collapse toward each other which allows 1/2 to 1/4" of the needle to remain after incineration.
A plastic syringe destruction device is disclosed in U.S. Pat. No. 4,860,958 to Yerman. The Yerman device employs a cylinder and piston compaction unit which uses heat to thermally smash complete plastic syringes, including the needle component, into a compacted mass. One or more plastic syringes are placed in the cylinder and the cylinder lid is closed. The syringes then are heated to temperatures between 100.degree. C. and 200.degree. C. to bring about melting of the syringes, as well as sterilization. The piston travels upwardly in the cylinder while the syringes are at temperature, thus compacting the softened or molten plastic syringes into the compacted mass. The Yerman device suffers from several disadvantages, the most important of which is that the syringes are not raised to a temperature high enough to destroy the metal needle portion of the syringe. After the plastic syringes have been compacted into a mass, the metal needles typically protrude from the plastic mass, thus still posing a danger to the operator. Although the needles may have been sterilized, puncture wounds caused by the needles are neither desired nor healthy.
A hypodermic syringe needle destroying and sterilizing apparatus and method is disclosed in U.S. Pat. No. 4,877,934 to Spinello. The Spinello device is aimed specifically at destroying the metal needle portion of the hypodermic syringe by using electrical resistance heating between electrodes. The hypodermic needle is placed in a carrier which contacts the upper portion of the metal needle closest to the syringe barrel. The carrier then carries the syringe over an upwardly sloping second electrode. As the needle point contacts the second electrode, electricity passes from the second electrode through the metal needle into the first electrode, thus causing resistance heating of the metal needle. In theory, the electrical resistance heating melts and destroys the metal needle. However, in practice, the electrical resistance heating may only soften the metal needle such that as the metal needle contacts the upwardly sloping second electrode, the metal needle bends outward. Although the Spinello device may heat the metal needle to a temperature high enough to sterilize it, typically the metal needle remains and poses the same health and safety hazard any other sharp instrument has. The Spinello device also comprises many moving parts which have the potential of jamming and wearing and no provisions are made for sterilizing the moving parts. Furthermore, this device operates along the full length of the needle which again leads to problems. If the needle has a crack in it or when the upper electrical grip holds the very top of the needle, it may break off causing an unburned part of the needle to fall into the particle tray. The needle destruction unit of the present invention burns off a section at a time, insuring the needle is destroyed and sterilized. Also there is not a provision in Spinello for filtering smoke and emissions as is provided by the present invention. The portal entry of the Spinello device has no provisions for being sterilized. Therefore, when the needle is placed in the device, whatever blood is on the needle may infect the portal entry area as well. In contrast, the present invention provides means for sterilizing the portal entry plate.
A disposable needle and syringe destructor unit is disclosed in U.S. Pat. No. 4,969,379 to Taylor, et al. The Taylor device essentially is a syringe guillotine. The syringe is inserted into a receiving hole a certain distance, and a spring-biased piston is hand actuated forcing a cutting member down on the syringe. The process is repeated until the entire syringe has been cut into smaller portions, which portions fall to the bottom of the container. Obviously, the Taylor device suffers from the disadvantage that the syringe is not sterilized and the metal needle portion, although in smaller pieces, still presents a safety hazard. After the Taylor device is full of syringe portions, it must be disposed of in much the same manner as the sharps' containers.
It appears that this device may violate the Federal Regulation Vol. 56, No. 235, Sect. 1910-1030, which prohibits shearing or breaking of contaminated needles. While rendering the syringe unusable, the blades become contaminated with whatever blood or foreign matter is on the needle or in the syringes themselves. Furthermore, shearing may cause an aerosol release of blood which is dangerous and therefore undesirable. Also, the Taylor device is a two handed device with which one hand must be used to press down on the chopper blade while the other hand holds the syringe. The needle destruction unit of the present invention can be operated with one hand. A user simply inserts a needle into the unit through the portal entry using only one hand and the needle is automatically incinerated.
One prior art device known as the Bacti-Cinerator III is a 120 volt plug-in flameless sterilizer model for inoculating loops, needles and culture tube mounts. The unit operates at 1500 degrees Fahrenheit, 815 degrees centigrade and has been on the market approximately ten years. It is accepted by the FDA as a safe way to sterilize needles. However, the Bacti-Cinerator does not contain a filtering system, so whatever biological elements are on the needles or inoculating loops are burned off and allowed to escape into the air. In contrast, the present invention provides that smoke and gases generated during incineration are filtered properly before being released into the room. Therefore, the present invention is generally safer and takes into account the FDA's concerns over emissions.
U.S. Pat. No. 4,565,311, dated January 1986 discloses a device for syringe disposal. This is a device for shearing needles and syringes. Parts from the sheared needles fall into a tray or container placed in the bottom of the machine. The machine is essentially a set of blades connected to a solenoid. A syringe is dropped down into an aperture where it falls into a cone shaped holding area. The blades then work back and forth against the needle and the syringe body chopping them into pieces. Disposal devices such as this may violate Federal Regulation Vol. 56, No. 235, Sect. 1910-1030 which states that contaminated needles and other contaminated sharps should not be bent, recapped or removed except as noted in Paragraphs D, 2, ViiA and D, 2, ViiB; shearing or breaking of contaminated needles is prohibited. When using this device, blood may be released as the needle or the syringe body is sheared. This would cause splattering inside the device which means that the blades would constantly be infected. There are no provisions made to sterilize the blades of this device. Therefore, the device may be an open source of contamination, particularly when the device would need repair. It may have to be decontaminated or steam cleaned prior to being worked on. While it destroys syringes by chopping them up into little pieces and rendering them unusable, the needles are still there, are still contaminated and still have the chance of sticking someone.
U.S. Pat. No. 4,628,169, dated Dec. 9, 1986 discloses an electrode needle destroyer. This device consists of a frame and cabinet with two electrodes, a transformer and a small tray for collecting needle fragments. This device uses electrodes to bum the needle off. However, it operates on burning the full length of the needle which requires more power than does the needle destruction unit of the present invention. The electrodes are very small and made of metal. The unit has a transformer plugged directly into a wall outlet so that as the needles are burned, it draws power through the transformer. This may cause a radio frequency signal that can interfere with the delicate equipment in operating rooms or a physician's office. This also reduces the portability of the device. Furthermore, there are no provisions in this device for removing smoke or emissions resulting from incineration. Also, the device is not practical because the electrodes may become coated with metal fragments and short out after a short number of uses.
U.S. Pat. No. 5,076,178, dated Dec. 31, 1991 discloses a device which heats and softens a syringe needle to sterilize it and then rolls the needle into a ball. This process leaves the needle intact although it is shaped into a spiral. The device relies on ultraviolet light and heat for sterilization. Tests have shown ultraviolet light to be efficient primarily on exposed surfaces but insufficient to deal with machine parts not directly under the beam. The device also crimps and shears the needle, which may also violate Federal Regulation No. 56, No. 235, Sect. 1910-1030. Also, the device requires 115 volts on a continuous basis and is not portable.
Therefore, it can be seen that there exists a need for an apparatus for sterilizing and destroying the metal needle component of a hypodermic needle syringe with a minimum of operator intervention and a minimum of moving or mechanical parts and which is in compliance with federal regulations. While past methods destroy a portion of the needle and may sterilize the needle, these devices do not do a complete job of destroying the entire needle component of the syringe, and the used hypodermic needle portion of the syringe is still not safe to the handler or for the environment. The present invention overcomes the disadvantages of the prior art by thoroughly burning and destroying significantly all of the needle portion of the syringe by continuously passing a sufficient amount of electricity through the needle, burning and destroying portions of the needle at a time. Any remaining needle portion, particularly the nub of the needle closest the syringe barrel, also has been heated, through electrical resistance heating, to a sufficient temperature for a sufficient period of time to sterilize any remaining needle portion. Unlike the prior art which acts upon only the base and tip of the needle, the present invention acts only on a small portion of the needle at a time, eliminating the need for the high amperages and voltages required by the prior art, and eliminating the problem of needles breaking between the base and tip and needles welding themselves to the electrodes as frequently occurs in the prior art devices. The present invention also prevents blood aerosol release and provides means for filtering out smoke and gases which may be produced during incineration.
One of the problems confronted by the present invention was to design electrodes that would not melt at temperatures needed for incineration (i.e., approximately 2800.degree. F.). Some of the prior deneedling devices utilize electrodes which cause portions of the melted needles to be welded to the electrodes. The present invention solves this problem by using electrodes comprised of carbon. Although portions of the melted needle may lightly adhere to the surfaces of the electrodes, they immediately come off or are forced off when another syringe is placed in the unit as described in more detail below.
Another problem inherent in some of the prior deneedling devices is that they require relatively high current to operate. Due to the fact that the apparatus of the present invention bums only small portions of the needle at a time, power requirements are for less than devices designed to rely on electrodes positioned at the base and tip of the needle, or which are otherwise designed such that they require a relatively high current to incinerate a needle. The relatively low current requirement allows the present device to use a rechargeable current source, as described below, which allows the present device to incinerate a number of needles before needing recharging, and to be small enough so as to be portable.
In accordance with a preferred embodiment of the present invention, a 12 volt rechargeable power source is utilized. The power source can be charged from total discharge to full charge in approximately five hours on a standard 300 milliamp charger. The power source is preferably comprised of ten 1.2 volt ni-cad batteries arranged in series. The needle destruction unit runs off of 7.2 volts obtained by tapping six batteries of the series arrangement. The filtering means comprises a fan which runs off of 12 volts obtained by tapping all ten of the ni-cad batteries. The arrangement allows up to approximately 80 needles to be destroyed before recharging as described in detail below.
Some advantages of using a relatively low current to incinerate the needles are that radio frequency interference is avoided, sparking and aerosol release are avoided, and mobility is enhanced in that the apparatus need not include a large power source. Moreover, the apparatus of the present invention can be used while it is charging.